Watch the Edge, Adam Clayton's Shock Performance With U2 Cover Band

Duo plays "Where The Streets Have No Name" and "Out of Control" with cover band Unforgettable Fire to stunned fans at New York club

U2 have spent the past couple of months bringing special guests - an Elvis impersonator, a Canadian U2 cover bandLady Gaga - onto the stage at their own shows. But on Wednesday night, they brought the act to a higher level when The Edge and Adam Clayton joined the New York-based U2 tribute band Unforgettable Fire at The Cutting Room, a club in New York that seats 450 people. 

Making the appearance even more special, the show was part of U2 fan site @U2's 20th anniversary celebration. Nobody involved with the event knew that half of U2 would even appear at the party until moments before they walked onstage. "It was mind-boggling," @U2 founder Matt McGee tells Rolling Stone. "Our whole crew has been trading texts all morning saying, 'Did that really happen?'"

Two months ago, the @U2 crew formally invited the band and their entire team to the party. The African Well Fund, a registered charity comprised of U2 fans that raise money to build wells in Africa, hoped to present their annual birthday card to Bono as part of the festivities. They also knew that U2 had an off-day from their Madison Square Garden residency and might enjoy the chance to meet their most passionate fans. "It was a million-to-one shot," says McGee. "As late as yesterday afternoon, we got an e-mail saying they had other commitments and couldn't rearrange their schedules."

But the U2 representatives did say that members of the band's management and publicity team might want to stop by. A large group of them showed up shortly after the party began and were given a detailed walk-through of the event, including a side door and VIP balcony. "All of a sudden Edge's guitar tech Dallas Schoo walked through the main entrance and stood at the check-in desk," says McGee. "I saw they weren't letting him in. I ran over and said, 'He's on the list! Let him in!'"

Schoo is a familiar site to U2 fans, and a crowd formed around him as McGee led him towards the stage. "He said to me, 'Listen, take me up the stage,'" says McGee. "'I'm going to play a few songs with Unforgettable Fire.' Looking back, I think his entrance was partially a planned distraction. It got the attention of all the fans, and Edge and Adam were able to slip in through a side door and up to the VIP area."

They made their way to the side of the stage as Unforgettable Fire were playing without being recognized by anyone. "I literally didn't see them until they were at the side of the stage," says McGee. "I thought to myself, 'Is this happening? Is this real? What are they doing here? What's going to happen next?'"

When Unforgettable Fire finished their next song, Schoo walked onstage and began talking to their guitarist Mick Normoyle. "He said to him, 'What's the setting on your rig for 'Streets?,'" says McGee. "He then picked up the instrument and began tuning it. At this point, we're still thinking Dallas is going to be the one playing."

The sight of Dallas tuning a guitar was enough to make the crowd go nuts, but then Clayton and Edge walked onstage and took over for their doppelgängers as the half-real/half-fake U2 hybrid kicked into "Where The Streets Have No Name." "Everyone erupted," says McGee. "It was unforgettable and just insane. I was just numb. Tribute Edge was standing right behind Real Edge and Tribute Adam was standing right behind Real Adam. There was such joy in their faces. I'm almost in tears watching how happy they were."

When the song ended, Edge and Clayton took off their instruments and posed for photos with the band. "The crowd kept chanting 'One more song,'" says McGee. "They then put their instruments back on and played 'Out of Control.' They took a group photo with the band and their security led them out through the side door. It was fantastic."

McGee is still in a state of shock. "They didn't have to do that," he says. "It's such an honor for the community of online fans. They did it to say thanks and share some recognition with folks that have been following them all these years."

At the end of the night, McGee stood onstage with his fellow @U2 staffer Sherry Lawrence. "I looked at her and said, 'For the 25th, the only way we can top this is to have the whole band come,'" he says. "But really, there's no way to top that. It's the most fantastic thing they could have done."